Yes, I believe it has something to do with Whatsapp...
- After I receive any audio notes I get this buzzing sensation...
- BTW Whatsapp is not yet w10m compatible.... hence the deepened voice messages (when I send one)
How is it random? It's clearly the buzz generated when the speaker is receiving current, when it's not fed anymore it pops. Sometimes it hangs in a loop doing this every 5 seconds. Poor quality components
Getting this even without WhatsApp, for me, Store and changing Volume triggers the clicking.
By the way, problem was reported to Microsoft and they are working on it.